Características de los pacientes que reciben ventilación mecánica en unidades de cuidados intensivos: primer estudio multicéntrico chileno / Characteristics and factors associated with mortality in patients receiving mechanical ventilation

Background: The outcome oí' mechanically ventilated patients can be inñuenced byfactors such as the indication of mechanical ventilation (MV) and ventilator parameters. Aim: To describe the characterístics of patients receiving MV in Chilean critical care uníts. Material and methods: Prospective cohort of consecutive adult patients admitted to 19 intensive care uníts ([CU) from 9 Chilean cities who received MV for more than 12 hours between September lst, 2003, and September 28th, 2003. Demographic data, severity of illness, reason for the initiation of MV, ventilation modes and settings as well as weaning strategies were registered at the initiation and then, daily throughout the course of MV for up to 28 days. ¡CU and hospital mortality were recorded. Resulte: Of 588 patients admitted, 156 (26.5 percent) received MV (57 percent males). Mean age and Simplified Acute Physiology Score-II (SAPSII) were 54.6±18years and 40.6±16.4 points respectively The most common indications for MV were acute respiratory failure (71.1 percent) and coma (22.4 percent). Assist-control mode (71.6 percent) and synchronized intermittent mandatory ventilation (SIMV) (14,2 percent) were the most frequently used. T-tube was the main weaning strategy. Mean duration of MV and length of stay in ICU were 7.8±8.7 and 11.1± 14 days respectively. OverallICUmortality was 33.9 percent (53patients). The main factors independently associated with increased mortality were (1) SAPS II ≥ 60 points (Odds Patio (OR), 10.5; 95 percent CI, 1.04-106.85) and (2) plateaupressure ≥ 30 cm Hfi atsecond day (OR, 3.9; 95 percent CI, 1.17-12.97). Conclusions: Conditionspresent at the onsetofMVand ventilator management were similar to those reported in the literature. Magnitude ofmultiorgan dysfunction and high plateau pressures are the most important factors associated with mortality).

Ventilación no invasiva en pacientes con exacerbacion de EPOC / Non invasive positive pressure ventilation in patients with COPD exacerbation

Se realizó un estudio prospectivo sobre la utilización de la ventilación mecánica no invasiva (VNI) en pacientes internados en Clínica Médica Neumonológica por exacerbación de la enfermedad pulmonar obstructiva crónica (EPOC), con el objetivo de evaluar la evolución, los cambios gasométricos, las comorbilidades y la mortalidad de los pacientes internados. Desde enero 2000 a enero 2003 ingresaron al estudio 39 pacientes, evaluados según normas internacionales en 54 internaciones, siendo clasificados como de grado grave y muy grave, dado que la medición del volumen espiratorio forzado en un segundo (VEF1) era del 26%. Veintinueve pacientes (74.4%) presentaron alguna comorbilidad. Como consecuencia de la aplicación de la VNI, el pH se incrementó entre la primera y tercera medición. El pH promedio inicial fue de 7.25 llegando a 7.33 a las 2 horas y a 7.39 al alta, en tanto que la pCO2 con promedio inicial de 83.8 mm Hg llegó a 67.8 mm Hg y 54.2 mm Hg en el mismo período. Treinta y cinco de los 39 pacientes fueron dados de alta con un período de internación promedio de 13.6 días. Cuatro pacientes (10.3%) fallecieron. Se concluye que con la aplicación de la VNI en pacientes con exacerbación de EPOC, el pH y la PaCO2 cambian significativamente en las muestras sucesivas, y que la adecuada capacitación del equipo de salud puede permitir el tratamiento de estos pacientes en áreas de menor complejidad. Deben ser tenidas en cuenta las posibles complicaciones que pueden sufrir los pacientes durante la internación, que pueden requerir la aplicación de ventilación invasiva.

This is a prospective study on the implementation of the non-invasive positive pressure ventilation (NPPV) to treat respiratory failure resulting from exacerbation of chronic obstructive pulmonary disease (COPD) in patients hospitalized in a Pneumological Unit. From January 2000 to January 2003, 39 patients were included during 54 different exacerbation events after being evaluated under international standards. They were classified as severe and very severe patients on the basis of their FEV1 values of 26%. Twenty nine patients presented co-morbidities. As a consequence of the NPPV treatment, the pH values increased between the first and last register as well as the pCO2 dropped in the same period. The initial mean pH values were 7.25 reaching mean values of 7.33 at 2 hours and 7.39 at the discharge; the corresponding pCO2 mean values were 83.8 mmHg, 67.8 mmHg and 54.2 mmHg. Thirty five patients out of 39 were discharged after a mean hospitalization length of 13.6 days. Four patients died. Apropriate training of health care staff in general facilities could allow the implementation of NPPV in addition to usual medical care to treat exacerbation of COPD. High morbidity situations could arise during hospitalization, so invasive ventilation must be necessary.